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<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<script>
  class Person {
    constructor(name, age) {
      this.name = name
      this.age = age
    }
    speak() {
      console.log(this)
    }
  }
  const p1 = new Person('tom', 28)
  p1.speak()
  const x = p1.speak
  x()
</script>

<body>

</body>

</html>